1. Technical Field
This application generally relates to data storage systems, and more particularly to techniques used with storing and accessing data on data storage systems.
2. Description of Related Art
Computer systems may include different resources used by one or more host processors. Resources and host processors in a computer system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as those included in the data storage systems manufactured by EMC Corporation. These data storage systems may be coupled to one or more servers or host processors and provide storage services to each host processor. Multiple data storage systems from one or more different vendors may be connected and may provide common data storage for one or more host processors in a computer system.
A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units, disk drives, and disk interface units. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and the storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units. The logical disk units may or may not correspond to the actual disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data in the device. In order to facilitate sharing of the data on the device, additional software on the data storage systems may also be used.
Data storage systems and host or servers may be configured in a network arrangement referred to as a Storage Area Network (SAN). Operations, such as data backups and restorations, may be performed with respect to data for one or more of the servers. Various technologies may be used in connection with storing and retrieving the backup data such as a single instance storage (SIS) technology which performs data deduplication to eliminate redundant data. SIS technologies manage duplicate copies of content by keeping a single copy of the content and providing a reference or token to the single copy. The reference or token may be used to describe multiple instances of a same copy of backed up data such as may be present, for example, when backing up a same set of data at different points in time.
In connection with SIS technologies, it may be desirable to utilize techniques for efficiently storing and processing the data in connection with the various operations performed. It may also be desirable to have such techniques be scaleable in accordance with one or more variables or parameters of a system within which the SIS technologies are utilized.